Drum drier mechanism



Oct. 27, 1959 L. HoRNBosTEL 2,909,849

DRUM DRIER MECHANISM Filed NOV. 25, 1955 2 Sheets-Sheet 1 4/ 4.a v b 57i@ @iig WM@ 4 w ,Mz/L55.

oct. 27, 1959 L. HoRNBosTEL 2,909,849

DRUM DRIER MEGHANISM i Filed Nov. 25, 1955 2 sheets-sheet 2 Il ns /zo I/Tr/ENZLDF Lowa Hom/Basra.

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i W I United States Patent O DRUM DRIER MECHANISM Lloyd Hombostel,Beloit, Wis., assignor to. Beloit Iron Works, Beloit, Wis., acorporation of Wisconsin Application November 25, 1955, Serial No.549,055

4 Claims. (Cl. 34-124) The instant invention relates to a dryer drum fora paper machine, and more particularly, to an improved dryer drumstructure. j

As conventionally employed in the art, dryer drums for paper machinedrying sections generally consist of a cylindrical shell, spaced headsextending radially across the shell to close the open ends thereof andcarrying means for journaling the shell for rotation, and means forintroducing a heat exchange lluid into the interior of the shell. TheYankee dryer drum has generallythe same structural arrangement, as nowused in the art, except that the Yankee dryer drum is ordinarily ofsubstantially greater size than the dryer drums in the conventionaldryer section of a paper machine. Nevertheless, in each case these dryerdrums (whether the large Yankee dryer drum or the smaller conventionaldrum) have certain operating limitations. The strength requirements forthe shell define a minimum thickness therefor; and the greater thethickness of the shell the slower the heat transfer therethrough. Also,the higher the steam pressure within the shell, the greater thethickness required therefor. In view of this, there are definitelimitations in shell size and usable steam pressure for any given shell,so that the maximum capacity of `the shell for drying purposes is alsolimited.

As will be appreciated, a given shell structure can withstand only acertain maximum steam pressure therein and this 'maximum steam pressurewhich may be maintained within the shell determines the maximum amountof heat which can be supplied to the shell and thus the maximum amountof drying which can be effected by passing a paper web over the shell.For years these limitations have been recognized and the industry hascontinued to use the conventional dryer drum structure.

In contrast, the instant invention is based upon the discovery that theusual heat exchange fluid, namely, steam may be confined in small pipesor conduits within the shell; and this steam (or any other heat exchangefluid such as hot oil) may thus be forced into the shell at pressuresubstantially greater than the pressure which the shell itself couldordinarily stand. Heat transfer from the heat exchange fluid within thesmall pipes or conduits is effected, according to the present invention,by the use of a relatively non-volatile liquid (which does not build upa pressure comparable to the heat exchange lluid at the temperaturesinvolved) and the uid is maintained in uniform contact with the innerperiphery of the shell by centrifugal force during rotation of theshell. The small pipes or conduits carrying the heat exchange uid arethus mounted adjacent the inner periphery of the shell so as to becontinuously immersed in the nonvolatile liquid which flows freelywithin the shell.

It is, therefore, an important object of the instant invention toprovide an improved dryer drum structure.

It is another object of the instant invention -to provide an improvedmethod of heating a dryer drum.

Still another object of the instant invention is to provide an improveddryer drum comprising a cylindrical ICC shell, a head closing each endofthe shell, and a steam conduit within the shell adjacent the shellinterior.

Other and further objects, features and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed disclosure thereof and the drawings attached heretoand made a part hereof.

On the drawings:

Figure l is a sectional view with parts shown in elevation takensubstantially along the longitudinal axis of rotation of a dryer drum ofthe present invention;

vFigure 2 is a sectional eleva-tional view taken sub-1 stantially alongthe line II-II of Figure 1;

Figure 3 is an enlarged detail view of the condensate drainage headeremployed in the practice of the instant invention; and

Figures 4 and 5 are views comparable to Figure l showing otherembodiments of the invention.

As shown on the drawings:

The reference numeral 10 indicates generally a dryer drum of the presentinvention including a cylindrical shell 11 having open ends closed byannular heads 12 and 12a bolted thereto and extending radiallythereacross. Each of the annular heads 12 and 12a, respectively, hasbolted thereto about its inner periphery an annular journal ring 14 and14a.

Journals 15 and 15a, each having peripheral mounting anges 16 and 16aand axially extending axle portions 17 and 17a are secured respectivelyto the annular journal rings 14 and 14a by screws 18 and 18a. Each ofthe journals is provided with an axially extending bore 19 and 19a. Thebore` 19 of the journal 17 receives a concentric conduit 20 which isaheat exchange iluid or steam inlet conduit. The conduit 20V isV securedinthe bore 19 by a centering plate 21, the plate 21 being secured to thejournal 17 by suitable screws 22. s

In like manner, the bore 19a of the journal 17a receives aconcentricconduit 20a which is held in place by a centering plate 21aaffixed to the journal 17a by screws 22a. Theconduit 20a is a heatexchange uid drainage line, or preferably a condensate drainage linelfor use with steam. vAs mentioned, lthe conduit'20 `is preferably asteam inlet line. l j

As those skilled in the art will readily appreciate, the instantinvention does not require that the steam or heat exchange fluid befedinto one `end of the shell 11 and taken out from the other end, eventhoughthis is the l most 'convenient and advantageous arrangement, as ishere shown in Figure 1. It will be appreciated that the steam inlet andcondensate drainage lines may be concentric, as shown in LloydHornbostel U.S. Patent No. 2,651,114, and thus bothlead through the samehead into the shell 11. In such case, it would be preferable to eX- tendeither the steam inlet or the condensate drain line the full axiallength of the shell 11 so `as to simulate the arrangement here shown.

As best shown in Figure 2, the steam inlet line.20 leads into the shell11 through one of the heads, in this case, the head 12 and a pluralityof radial steam pipes 23 through 34 extend from the steam inlet 20 atthe axis of the shell 11 to an annular steam header 35` adjacent the endof the shell 11 whereat the head 12 is located. The radial pipes 23through 34 are connected'to the steam inlet 20 and the annular steamheader 35 so as to provide uid communication therebetween. In thisrespect, it should be noted that it is generally preferable to have theconduit system within the shell formed as an integral part and this mayrequire a change in the conventional dryer drum structure in that one ofthe heads 12 or 12a may be aixed thereto so that it may be morev in onehead 12a to ll and empty the shell but this is a' matter of `mechanicalexpediency which does not form a part of the instant invention.

A plurality of heat exchange conduits or heat eX- change fluid conduits36 through 47 are mounted adjacent (but closely spaced from) the innerperiphery of the shell 11 and in communication with the annular steamheader 35 to receive the steam therefrom. The conduits 36-47 areperipherally spaced and they extend along substantially the entirelength of the shell 11 from closely adjacent the one head 12 to closelyadjacent the opposite head 12a. The conduits 36-47 are secured to theannular steam head 35 to form a sturdy structure; and the conduitsextend from the steam header 35 to an annular condensate header 48 whichis also secured to the conduits 3647. The spent steam or other heatexchange uid is thus passed from the conduits 36-47 into the drainageheader 48 which is positioned closely adjacent to the head 12a and theinner periphery of the shell 11.

A plurality of radial condensate or drainage pipes extend from thedrainage line 20a radially outwardly and into the annular drainageheader 48; and only the radial pipes 49 and 50 can be seen in Figure 1.It will be appreciated that it is preferable to employ radial drainagepipes in an arrangement substantially the same as that shown for theradial steam pipes 23-34, so that more than the two drainage pipes 49and 50 here shown Xare employed in the instant structure. Actually, theview of the drainage header 48 comparable to the view of Figure 2 forthe steam header 35 would be substantially identical thereto, exceptthat the condensate header 48 is larger than the steam header 35 andextends radially outwardly a slightly greater distance for reasons whichwill be explained in the next paragraph.

Referring now to Figure 3, it will be seen that the steam conduit 42feeds generally into the center of the drainage header 48, but the steam`conduit 42 is somewhat smaller in size so that the drainage header 4Sextends radially outwardly beyond the steam conduit 42. The radialdrainage pipe 50, however, extends into the drainlage header 48 radiallybeyond the steam conduit 42 to closely adjacent the radially outwardportion of the drain header 48. In this way condensate which may beformed in the steam conduit 42 and owed into the drain header 4S will bethrown by the centrifugal force of the rotating shell 11 against theradially outward portion of the drainage header 48 so as to maintain acondensate level L thereat and the radial condensate pipe 50 extendsbeneath this level L (which is radially outward from the steam conduit42) so that condensate will be continuously removed through the radialcondensate pipe 50 and from there into the axially aligned drainage line20a.

It will be readily appreciated that the relatively small diameters (i.e.about 2 to 20% of the shell diameter) of the steam conduits 36-47 willpermit the use therein of steam of much higher pressure than could beused in the form of free steam within the shell 11. The conduits 36-47are preferably parallel units closely to the shell 11 as here shown; butthey may also be arranged as helical coils, etc., the main purpose beingto supply heat as close to the shell as possible. In this way, muchgreater heat input is made possible. In order to transfer this heat fromthe conduits 36--47 to the shell 11 a liquid is maintained in the shell11. The liquid A is held uniformly against the entire inside peripheryof the shell 11 by centrifugal Iforce so as to continuously maintain alevel La around the inner periphery of the shell 11 which will submergethe conduits 315-47. Preferably the level is just suflicient to coverthe conduits 36-47, since a minimum weight of liquid A is desired.

The liquid A employed is a heat conductor, of course, so that heat maybe conducted readily therethrough to the shell 11 and it is also asubstantially non-volatile liquid so that excessive vapor pressures arenot built up within the drum 11. A number of relatively non-volatileoils may be used relatively non-volatile heat exchange liquids (such asDowtherrn) may also be used. In order to obtain best conductivity lowmelting metals (such as Roses metal) may be used. The main requirementis that the liquid A is in fact a relatively fluid liquid at theoperating temperatures so that it can be maintained against the innerperiphery of the shell 11 in a substantially uniform manner by thecentrifugal force generated through conventional rotation of the shell11; and the liquid A will, of course, be in constant movement againstthe shell 11 so that turbulence therein will aord heat transfer throughconvection (in a greatly accelerated manner). As shown by the arrows a,a in Figure 2, the traveling inner periphery of the shell 11 gives amaximum velocity to the liquid iilm immediately adjacent thereto;whereas the liquid A at the level La tends through inertia to resistmovement so that turbulence in the direction indicated by the arrows a,a is constantly created. Turbulence creating ilow devices may also beused.

Although the heat exchange fluid ordinarily preferred for use in thepractice of the instant invention is steam because of its availability,it will be appreciated that other heat exchange fluids such as heatedoils, etc. may be employed in the practice of the instant invention.

It will thus be seen that the instant invention comprises a method ofheating a dryer drum shell 11 which comprises holding a relativelynon-volatile liquid A uniformly against the entire inside periphery ofthe shell 11 with centrifugal force, immersing a heat conductive solid(in the form of the conduits 36-47) in the liquid A, and heating thesolid conduits with a fluid such as steam maintained separate and apartfrom the liquid A, or heating the solid conduits by condensing a uidsuch as steam thereagainst to heat the same.

Referring to Figure 4, the reference numeral indicates generally anotherdryer drum embodying the invention, in a view comparable to the view ofFigure l wherein parts having identical functions to the parts shown inFigure l are indicated by the same reference numeral, only in the 100series. The cylindrical shell is thus 111 and it is closed by heads 112and 112a bolted thereto. Each of the heads 112 and `112a, respectively,has bolted thereto about its inner periphery an annular journal ring 114and '114:1 and one of the heads 112a has a capped drain and inletconduit 113 which may be used to flow heat exchange lluid into the shell111 or drain the same therefrom.

Journals 115 and 115:1, each having peripheral mounting flanges 116 and116a and axially extending axle portions 117 and 117:1 are securedrespectively to the annular journal rings 114 and 114a by screws 118 and118a. Each of the journals 115 and 115a is provided with an axiallyextending bore 119 and 119a. The bore 119 of the journal 115 receives aconcentric conduit 120 which is a heat exchange fluid (steam) inletconduit; and the conduit 120 is secured in the bore 119 by a centeringplate 121 secured to the journal 115 by suitable screws 122.

In like manner, the bore 11911 of the journal 115a receives a concentricconduit 12th: which is held in place by a centering plate 121a axed tothe journal 11511 by screws 122a. The conduit 12tlg is a heat exchangeiluid drainage line, or preferably a condensate drainage line for usewith steam, which is preferred for use in the invention.

In the embodiment 100, steam conduits within the shell are provided inthe form of spiral pipes 152 and 153. As will be seen from Figure 4, thesteam inlet conduit 120 feeds through a radially aligned aperture 154into a first loop 152a of one of the spiral pipes 152, which sweepsrearwardly from the opening 154 and upwardly to closely adjacent theshell 111 and then sweeps forwardly (in the front half of the drum 100not shown in the view of Figure 4) and downwardly to start the secondloop 152b of the spiral. The spiral pipe i152 continuously followsclosely to the inner periphery of the shell 111 through a number ofloops until at the right-hand side of the shell the last loop 1-521sweeps backwardly and upwardly and then connects into the drain conduit120a through a radially aligned opening (not shown) which issubstantially opposite to an opening 155 in the drain conduit 120:1which receives the last loop 153,1c of the second of the pair of spiralpipes 152 and 153. It will also be appreciated that the second spiralpipe 153 is fed steam through a radially aligned opening (not shown)that is opposite the opening or inlet 154 in the inlet conduit 120. Thefirst loop of the spiral conduit 153 is thus shown at I15311 at theleft-hand side of the drum 100 in Figure 4. It will be appreciated thatother spiral pipe arrangements may be employed and this is merely anexample of a type of spiral piping arrangement which may be found moreadvantageous or more easily constructed than the arrangement ofFigure 1. In the operation of the drum t100 a liquid B, such as theliquid A hereinbefore described, is held uniformly against the insideperiphery of the shell E111 by centrifugal force so as to continuouslymaintain a level Lb around the inner periphery of the shell which willjust submerge the helical conduits 152 and 153.

Referring now to the drum 200 of Figure 5, wherein parts comparable tothe parts shown in Figure l are indicated by the same reference numeralin the 200 series rather than the 100 series, it will be seen that theentire structure in Figure 5 is the same except for a centrally mounteddrum or cylinder 260 around which the spiral conduits 252 and 253 arewrapped. The centrally positioned drum is Secured to the inner ends ofthe inlet conduit 220 and the drain conduit 220z so as to ill upsubstantially the entire volume within the shell 211 and to leave only arelatively small annular chamber between the shell 211 and the outerperiphery of the drum 269 and this chamber is lled with a liquid C whichis the same as the liquids A and B in the previously described devices,except that the liquid C need not be held against the inner periphery ofthe shell 211 by centrifugal force but is combined thereagainst by thepresence of the centrally positioned drum 260. As here shown, a level Lcis maintained by centrifugal force in the drum 200, but it will beappreciated that the entire inside of the drum 200 not lled by theinside drum 260, which would include hollow portions P of the trunnionmight be filled with liquid without interfering in any Way with theoperation of the instant device. The drum 260 thus affords means whichwill permit the operation of the dryer 200 at slower speeds. The drum260 is, of course, a hollow closed body so as to have minimum weight,but to afford additional supporting structure for the spiral conduits252 and 253 and the interior of the shell 211 generally.

It will be understood that modifications and variations may be effectedwithout departing from the spirit and scope of the novel concepts ofthis invention.

I claim as my invention:

l. A dryer drum comprising a cylindrical shell, a head closing each endof the shell, a stem inlet line leading into the shell through one ofsaid heads, a plurality of radial steam pipes extending from the steaminlet at the shell axis to an annular steam header adjacent one end ofthe shell, a plurality of steam conduits mounted adjacent the insidewall of said shell receiving steam from said inlet line through saidradial pipes, said conduits being rotatable during rotation of the drum,a condensate drainage line leading from the shell through one of saidheads receiving steam from said steam conduits, and a uid heat exchangemedium interiorly of the drum and essentially entirely covering thesteam conduits during rotation of the drum to transfer heat from saidconduits to the shell.

2. A dryer drum comprising a cylindrical shell, a head closing each endof the shell, a stem inlet line leading into the shell through one ofsaid heads, a plurality of steam conduits mounted adjacent the insidewall of said shell receiving steam from said inlet line, and beingrotatable simultaneously with the shell, an annular condensate headerreceiving one end of each of said steam conduits, and a condensatedrainage line leading from the shell through one of said heads receivingsteam from said steam conduits through said condensate header, the steamconduits being substantially immersed in a lluid heat exchange mediumimpelled outwardly during rotation of the shell into contact with theinside wall thereof to transfer heat from said conduits to the shell.

3. A `dryer drum comprising a cylindrical shell, a head closing each endof the shell, a stem inlet line leading into the shell through one `ofsaid heads, a plurality of steam conduits mounted adjacent the insideWall of said shell receiving steam from said inlet line, said conduitsbeing rotatable during rotation of the shell, an annular condensateheader receiving one end of each of said steam conduits, a plurality ofradial condensate pipes extending into said annular condensate headerradially beyond the steam conduits received thereby, and a condensatedrainage line leading from the shell through one of said heads receivingsteam from said steam conduits through said condensate header and pipes,the shell being constructed to permit unrestricted outwardly impelledflow of a uid heat exchange medium into contact with the shell insidewall circumferentially therearound and in covering relation with thesteam conduits to transfer heat therefrom to the shell.

4. A dryer drum which comprises, a cylindrical shell closed at oppositeends, one of said ends receiving a steam inlet line and the other ofsaid ends a condensate discharge line, a plurality of steam conduitsadjacent the shell inner wall communicating with the steam inlet lineand mounted for simultaneous rotation with the shell, and a condensateheader connecting with the steam conduits and with the condensatedischarge line, the shell interior providing an essentially open chamberfor containing a fluid heat exchange medium to be impelled outwardlyduring rotation of the shell to substantially cover the steam conduitsand transfer heat therefrom to the shell.

References Cited in the file of this patent UNITED STATES PATENTS695,041 Fues Mar. 11, 1902 2,365,271 Hornbostel Dec. 19, 1944 2,367,578Helin Jan. 16, 1945 2,547,086 McDermott Apr. 3, 1951 2,586,829 KelseyFeb. 26, 1952 2,844,887 Hornbostel July 29, 1958 FOREIGN PATENTS 17,564Great Britain Aug. 23, 1909

